Preferred 4-slot board variations?

Hi all, completed my first significant repair for a MV4 board with corroded traces (batt acid) and dead ram, and I'm trying to decide if I should keep my MV4T or the newly repaired MV4?

The MV4T works well enough with the exception that the sound on slots 1 and 2 are scratchy if the carts are fully seated (have to wiggle them up a little). I have already used contact cleaner on the two finicky slots with little luck, but have not tried deoxit yet.

What is the typical failure point for the MV4 boards? Is it the top board or the bottom board? Is it worth pulling solid card slots from a spare parts board and replacing the flaky slot 1&2 on my MV4T?

Any suggestions or opinion would be appreciated.

The most common failures on MV4's I've seen (minus physical damage) are bad ram/z80/YM2610.

The only time I've swapped slot connectors is when there was physical damage to them. I think you should try a good cleaning with deoxit before spending the time swapping them.

I use Xian Xi's technique

https://www.youtube.com/watch?v=D6NM-RkwWFQ

If you do end up swapping, be aware there are a couple different slot connector designs. The main difference being the shape of the pins in them. They should all be interchangeable, but might just look weird having mixed ones.

Thanks Ack, yeah, one of the connectors has damage to the exterior shell, so I considered doing the swap even though only the audio is finicky. But between the two 4 slots, neither is more reliable than the other? Seems like with the MV4T variants, biggest change is the smaller form factor and the change to the NEO-244s to cut down on all the LS244 and FS244 ICs. The NEO-244s look a lot less intimidating to swap out, but I guess if the MV4s top board rarely fails, it is a moot point.

I think all the 4 slot models are about the same reliability wise. The only real difference I have seen are the original batteries on the MV4F* seem to be more prone to leakage then the MV4s.

I prefer the MV4's mainly because they do have the 7400 series ICs. You can pull, test, replace those with brand new ones as needed. With the custom NEO-XXX chips you are forced to get replacements from parts boards and hope it works.